Serena Williams in a race against time to get healthy for the French Open

Serena Williams played her matches in Madrid with her left thigh heavily taped. (Clive Brunskill/Getty Images)

ROME -- Serena Williams' participation in this week's Italian Open is in doubt after suffering an upper leg injury last week at the Madrid Open, which forced her to withdraw before the quarterfinals.

"I'm taking it a day at a time," Williams told reporters in Rome. "We'll see as the week goes on. I have the rest of the day off and I'll see how I feel tomorrow."

Williams was able to hit balls in practice on Monday, but is unsure how quickly her body will recover. The top seed in the tournament, Williams has a bye into the second round and could play as late as Wednesday. She says her Madrid withdrawal wasn't precautionary.

"I don’t do anything out of precaution anymore," she said. "I think you live once and anything can happen tomorrow. I physically couldn’t play. I was in a lot of pain and was unable to continue. When I am playing I want to give hundred percent. I want to go out there and I want to give the fans everything they deserve and everything they've come to see, and I wasn't even close to being able to do that there."

Williams, the defending champion in Rome, is racing time to heal so she can defend her title at the French Open, which begins on May 25. She goes into this stretch of the season with a different perspective than when she was younger.

"Throughout my career there were times where I thought I have to defend, I have to defend," she says. "Now I'm at a point in my career when I don't have to do anything. Obviously I want to win. I wanted to win Madrid, I would love to win Rome, obviously I would love to do well and win Paris. But I don't feel that pressure anymore."